SFDM: A Data Management Model Considering Stock And Flow

We proposed a new data management model, named Stock and Flow Data Model (SFDM). SFDM regards every entity as an object and records the change of its properties. We utilize the accounting methodology to differentiate and process stock data and flow data. The current status of an object is the result of accumulation of all of the past changes, but not the direct modification. The model uses Entry, a form of {When, Entity, Property, Quantity Change, Quality Change} to record the property changes of an object, and accumulates these changes as the status of the object at different time points. The Model is easy and flexible to apply to real applications, and supports operations such as rollback, split and merge.We also studied the model under multi-user environment. The Multi-User Stock and Flow Model allows users to exchange their knowledge about the property change of an object in the form of entry. Users can judge the correctness of the incoming entries and accept those valid ones..By extending the functionalities of RDBMS and developing object-oriented aggregate function, object diagram, etc, we implemented the model on the basis of current available software resources. We also discussed how to apply the model in real business and implemented a simple electronic name card system, which has some advantages over other similar systems that are not based on Stock and Flow Model.In the Multi-user Stock and Flow Model, some of the entries received by a user is valid while some others not. For a large-scale application, the volume of incoming entries would be enormous, so computer-aided decision-making is very necessary. We explored how to use Decision Tree Classification to distinguish incoming entries, and suggested using Mutual Information Coefficient instead of Gain Ratio in the process of decision tree building.The coding of entry aforementioned is redundant in some cases, e.g., the entity identifier occurs repeatedly if a batch of entries is all about one entity. We discussed how to extend the form of entry into various syntaxes. By doing so, entries can be expressed in a more relevant syntax such that the coding would be terser.